Kiln charging means and method



y 20, 4 A. A. CLARK 2, 0, 53

KILN CHARGING MEANS AND METHOD Fil ed Feb. 5, 1944 s sheets-sheet 1 u '51 mnun'nnmm Y AVERYA. CLARK 172 INVENTOR.

ATTORJVEY' May 20,1947. A. A. CLARK 2,420,653

KILN CHARGING MEANS AND METHOD Filed Feb. 5, 1944 3 Sheets-Sheet 2 34 J9 ,C Z6 Z7 5' 49 do so 1:

- 29 s l 26 45 I 23 jg 3 2a 33 23 5 l 79 41344 ma I .8 '2/ 7 AVERY A. CLARK INVENTOR.

ATTORNEY May 20, 1947. CLARK 2,420,653

KILN CHARGING MEANS AND METHOD AVERY A. CLARK IN V EN TOR.

A TTORIVEY damage to kiln linings.

Patented MayZO, 1947 KILN CHARGING MEANS AND METHOD Avery A. Clark, Denver, 0010., assignor to The Great Western Sugar Company, Denver, 0010., a corporation of New Jersey Application February 5, 1944, Serial No. 521,237

17 Claims.

1 This invention relates to the charging of divided material into kilns or the like, and more particularly to a method of and apparatus for charging coke and limestone into a vertical lime kiln. As understood herein, divided material comprises solid matter in a plurality of pieces or particles which differ either in size or specific gravity. Also, the method and apparatus of this invention are useful in the charging of divided material into blast furnaces, retorts, gas producers and apparatus of a similar nature, so that it will be understood that the term "kiln or the like" as used herein refers to all such types of equipment, or equipment for carrying out similar processes.

In a lime kiln, coke and limestone are charged into the top of the kiln, and the materials gradually work their way down the kiln, through a pre-heating zone in the upper portion of the kiln, then through a reaction or fire zone in the central portion of the kiln, where the coke is burned or reacted with limestone, or CaCOa, to produce carbon dioxide gas, or CO2, and burned lime, or CaO. The CO2 passes upwardly to be drawn off at the top or near the top of the kiln, while the CaO passes downwardly through a cooling zone to be removed from or near the bottom of the kiln. The products CO2 and CaO are particularly useful in processes such as sugar refining.

In lime kilns--and particularly those forming a part of, or used in conjunction with, sugar refining equipment-it isim'portant that the combustion of coke and the reaction between coke andlimestone be carried out as efilciently as pos sible, since the coke and limestone are considerable items in raw material costs.

Since limestone is much heavier than coke, and also is much more diflicult to handle and therefore is usually supplied in different sizes, the coke and limestone tend to segregate in the kiln, particularly when merely dumped in an uncontrolled manner into the kiln. Such segregation tends to produce pockets of unburned limestone, which upon-removal from the kiln either must be discarded as unsuitable or will not produce the desired reaction in the sugar refining process. Also, such segregation tends to produce excessive concentration of zones of coke, resulting in the uneven and off-quality production of CaO, and also producing erratic fire conditions causing severe Needless to say, it is important that the mixture of coke and limestone be maintained in the furnace in the correct proportions and it is also important that all parts 2 of the furnace be supplied with the divided materials equally.

In other operations, such as the production of iron in blast furnaces, or the production of heating or illuminating gas in gas producers, the charging of coke and ore, or other divided materials, is desirably uniform and performed in such a manner that the segregation of heavier and lighter divided materials, or larger .and smaller lumps, is avoided. Previous practice of charging by merely dumping in skips of coke, iron ore, limestone, etc., either alternately or with the divided materials mixed, does not produce the optimum results because the divided materials tend to pile up in the center of the kiln or furmace, and the heavier or larger particles roll to the outside of the cone-shaped pile thus produced. Also, as the material moves down in the kiln or furnace, the tendency for segregation is much more pronounced than would be the case if the level of the material were maintained substantially uniform across the furnace or kiln.

.Among the objects of this invention are to provide a method of charging divided material into a kiln or the like which will result in a substantially uniform deposition of such divided material; to provide such a method-particularly for charging divided material consisting of heavier and lighter or larger and smaller lumps tending to segregate in the kiln-which will largely overcome the tendency for such segregation; to provide such a method by which a substantially uniform distribution of the material or mixture of materials may be obtained at a predetermined level across the kiln or the like; to provide such a method which is specially adapted for charging divided material into a vertical kiln; to provide such a method which'is particularly adapted for charging lumps of coke and limestone into a lime kiln; to provide suitable apparatus for carrying out the above method; to provide such apparatus which includes a movable spout for charging such material into a kiln or the like; to provide such apparatus in which a desired path of movement or travel of the spout is obtained, whereby the above method is effectively carried out; to provide such apparatus which is relatively rugged in construction and therefore requires little attention during use; to provide such apparatus which will insure that the divided material will be charged into the kiln in measured uniform increments; to provide such apparatus which is adaptable for use in different types of kilns or the like; and to provide such crements along a path, preferably spiral, which extends first to the inner and then to the outer portion of the cross section of the kiln. In still further accordance with this invention, the material is charged into the kiln along a spiral path, from a point adjacent the center of the kiln to a point adjacent the periphery of the kiln, and then in reverse direction along a spiral path back to the center of the kiln. Preferably the convolutions of the spiral path are closer adjacent the periphery and farther apart near the center of the kiln, so that cross-sectional portions of substantially equal areas are included between each pair of adjacent convolutions. Also, the. spiral paths are interposed or interwoven with each other, so as to distribute the material more evenly over the cross section of the kiln.

Apparatus for carrying out the above method may include a rotatable platform and a reciprocable carriage mounted on the platform, the carriage being provided with a longitudinally moving belt which at some point along its length is always under the discharge end of a hopper disposed above the center of the kiln. The belt preferably discharges into a gas-sealing device, such as a tourniquet or spider comprising a shaft provided with equally spaced paddles and rotated at a uniform speed in a cylindrical hous- 111g.

The belt preferably feeds into the upper portion of the cylindrical housing, and the mixture of divided material is discharged from the lower portion of the housing into a feed spout which is mounted on the carriage and which extends through the platform and into the interior of the kiln. The belt movement insures that equal increments of material will be fed to the kiln through the spout, irrespective of which portion of the belt is under the hopper. The carriage preferably moves at a faster rate when the spout is adjacent-the center of the kiln, so that, as the platform rotates at a relatively uniform speed,

- the spout will move inwardly or outwardly different radial distances during each revolution of the platform. Such variation in speed during reciprocal movement may be obtained by a reversible lead screw having a variable pitch.

Other novel features and the elements of an embodiment of this invention will be apparent from the more detailed description which follows, taken in connection with the accompanying drawings, in which:

Fig. 1 is a front elevation of apparatus constructed in accordance with this invention, and adapted to charge mixed lumps of coke and limestone into a lime kiln;

Fig. 2 is a plan view illustrating the path of travel of a feed spout of the apparatus of Fig. 1;

Fig. 3 is a cross section of the apparatus of Fig. 1;

Fig. 4 is a plan view of the apparatus;

Fig. 5 is a side elevation, partially in section, of

a lead screw and other parts forming a portion of the apparatus; and

Fig. 6 is a dlmetric drawing of mechanism for effecting reversals of the carriage during reciprocal movement thereof.

Apparatus constructed in accordance with this invention, as in Fig. 1, includes a rotating platform P atop a kiln K, and a carriage C mounted on the platform and reciprocated by a reversing lead screw S. Divided material M consisting of a mixture of coke and limestone in the proper amounts, is carried to a bin B by a skip or other suitable conveyor, and is charged into the kiln by the apparatus. As in Fig. 3, carriage C is provided with a feed spout 8 to which equal increments of the mixture of coke and limestone are supplied in a suitable manner, such as explained later. The feed spout 8 extends through the platform, the lower end thereof terminating within the kiln at any desired level, such as a short distance above CO2 outlets 9.

In accordance with this invention, the carriage C is reciprocated in such a manner that a uniform layer of coke and limestone will be deposited in the kiln, at a predetermined level therein. Preferably, this is accomplished by reciprocation of the carriage so that the feed spout, in moving from the full to the dotted positions of Fig. 3, and vice versa, will follow a path such as indicated in Fig. 2. Thus, in moving from the full position of Fig. 3, at the periphery of the kiln, inwardly to the dotted position of Fig. 3, at the center of the kiln, the spout will follow the spiral path indicated by the full line I0 of Fig. 2, with the platform F rotating in a clockwise direction, as viewed from above. In moving from the center back to the periphery, the spout will follow a spiral path such as indicated by the dotted line ll of Fig. 2, which path is preferably interposed, as far as possible, with the spiral path of movement of the spout moving from the periphery of the kiln to the center thereof. It will be understood, of course, that since the rotation of the platform is always in the same direction, the two spiral paths cannot be completely interposed, but must cross each other at two points during each revolution of the platform.

It will be observed that the distance between adjacent lines indicating the path of the feed spout near the center of the kiln is much greater than the distance between adjacent lines indicating the path of the feed spout near the periphery of the kiln. The distance between these lines is such that equal areas are included between each pair of adjacent lines. To produce such paths, the feed spout is moved at a much greater rate as it approaches the center of the kiln so that the same area will be covered by each increment of feed. Thus, as the spout moves from the periphery to the center of the kiln, a uniform layer of the mixture of coke and limestone is deposited in the kiln, and as the spout moves from the center back again to the periphery of the kiln, a second uniform layer is deposited on top of the first. Since these layers are relatively flat, there is little or no opportunity for the piling up of material and resultant segregation of coke and/or limestone.

The platform P is rotatably mounted by means of flanged wheels l2, which rest on a track formed by the upper surface of a ring gear I3 which encircles the top of the kiln. The platform is rotated by a pinion l4 which engages ring gear l3, the pinion being driven by a motor l5 mounted on the platform. Motor I5 is directly connected to a speed reducer 6 which drives a bevel pinion I! through a chain and sprocket arrangement l8. Bevel pinion meshes with a bevel gear l9 keyed to one end of a vertical shaft mounted in a bearing 28 attached to the edge of platform P. Drive pinion I4 is keyed to the lower end of this shaft, and through the speed reducer and the reduction in speed due to the sizes of the various gears and pinions, as shown, the platform is rotated at a relatively slow but uniform rate, such as about 1 R. P. M.

As in Figs. 1, 3 and 4, the carriage C is mounted on wheels 2|, which roll along rails 22 which are attached to platform P and extend out over the edge of the platform at one side. Lead screw S which reciprocates carriage C across the platform as the platform rotates, is mounted in bearlugs 23 adjacent each end thereof and is driven through a reversing gear arrangement, described in detail later. Thi reversing gear arrangement is driven by a drive gear 24 engaging ring gear I3. Thus, as the platform rotates, the varying reciprocal movement of the carriage on the platform will be proportional to the speed of the platform, so that a uniform layer of material will be deposited during a predetermined number of revolutions of the platform, irrespective of the actual speed of the platform. Desired variation in the rate of speed of the carriage during reciprocation may be obtained by a varying pitch of thread 25 of the lead screw.

To supply material to the feed spout, the carriage is provided with a belt 25 which moves around rollers 21 to carry the divided material from the lower end of bin B to a gas-sealing device, such as a tourniquet or star feeder. Such a device may comprise a shaft 28 provided with paddles 29 and rotating in a cylindrical housing 3|]. Belt 26 and shaft 28 of the gas-sealing device are driven by a motor 3|, in a manner described later. Divided material is carried by the belt to'a receiving bin or inlet 32 for the housing, and the paddles preferably are equally spaced so that'no substantial gas leakage is permitted in the omration of the mechanism. As the carriage is reciprocated to move the spout from the full to the dotted position of Fig. 3 and back again, the uniform movement of the belt insures that equal increments of material will be deposited from the feed spout 8.

The bin B may be provided with a control outletwhich rotates with the platform, but slides alon the upper portion of the carriage during reciprocation ofthe latter. For the former purpose, the bin outlet includes a cylindrical guide 34 which rotates about lower end 35 of the bin, and for the latter purpose, includes a box 36 which may be provided with wheels (not shown) which roll along rails 39 formed by the upper edges of the carriage sides. Box 35 is provided with a slot 31 and forwardly diverging baflles 38, as in Fig. 4, for regulating the discharge of the mixture of coke and limestone from the bin onto the belt. If desired, a suitable plate valve or the like may be substituted for slot 31.

Electricity for motor I5 may be supplied by rotary sliding contacts mounted on bin B and its outlet, and cables connecting the contacts with the motor. Electricity for motor 3| may be supplied by sliding contacts on the outlet and connected with the contacts for motor I5, along with cables extending along the carriage to motor 3|.

The upper end of the kiln is sealed in a number of places so that the C0: is forced to pass through the outlets. To provide an oil or water seal between the platform P and the top or the kiln, a circular baflle 48 extends downwardly from the platform P into a storage well 4|, attached to the top of the kiln. Escape of gas through feed spout 8 is prevented by the mixture of coke and limestone in the feed spout and in housing 38, combined with the sealing effect of paddles 28 in the housing. In addition, an opening 42 in the platform, through which the feed spout extends, is sealed by baille plates 43 which extend downwardly from all edges of a cover 44 suspended from beams 45 of the carriage framework and sealed thereto where spout 8 passes through it. Bafiie plates 43 extend into a storage well provided on the platform between rails 22 by an end beam 46 and an upwardly extending flange 41. Flanges 48 extend upwardly from the platform around the edges of the openin 42 to complete the water well. As will be evident from Fig. 3, the end baflle plates 43 are spaced apart sufficiently to permit reciprocation of the carriage, one plate approaching close to an end flange 48 when the feed spout is in the full position of Fig. 3, adjacent the periphery of the kiln, while the opposite end plate lhpproaches the opposite flange 48 when the carriage moves to the opposite position with the feed spout in the dotted position. Flange 41 is, of course, positioned to permit full movement of the carriage. With the gas-sealing device full of divided material, and the storage wells filled to a sufficient depth with oil, the upper end of the kiln is sealed so that the C02 produced therein will not escape, but will be forced to pass through outlets 9.

Motor 3|, for driving the belt 25, and shaft 28 of the gas-sealing device, are mounted on the carriage at the end opposite the lead screw. As in Figs. 3 and 4, a sprocket on the motor shaft drives, by means of a chain 49, a sprocket 58 mounted on a shaft which extends horizontally to the opposite side of the carriage, and by a similar chain and sprocket arrangement, drives shaft 28. Roller 21, at the discharge end of the belt, is mounted on a shaft 5|, and is driven through a gear 52 keyed to shaft 5| and meshing with a pinion on shaft 28 disposed beneath gear 52.

The lead screw S may be constructed in any suitable manner. For instance, as in Fig. 5, the lead screw may comprise a pipe 53 provided at each end with a short section 54 of shafting and a collar 55 for attaching the shafting. Each shafting section rotates in a bearing 23, of Fig. 3, and a drive gear 56 is keyed to the shafting section opposite the carriage. Thread 25 may be formed in any suitable manner, as by round stock bent to shape and welded to pipe 53 with the convolutions of the thread corresponding to the convolutions of the path which feed spout 8 is to traverse, with due consideration for the relation between the rate of traverse of the carriage and the rate of rotation of the platform, i. e. whether the lead screw is to turn one, two, or a different number of times for each revolution of the platform. In the example shown, for the sake of simplicity, the lead screw has thirteen threads, and there are six full line and six dotted line convolutions of the feed spout paths in Fig. 2, so that the lead screw turns at a rate of two revolutions during each revolution of the platform. However, it will be understood that any other number of revolutions of the lead screw, such as one, for each revolution of the platform, may be utilized. 3

As in Fig. 5, to move the carriage with the least friction and wear, the thread 25 of the lead screw engages a. grooved roller 61 mounted for horizontal rotation about a pin 68 which extends between the upstanding arms of a standard 68. Standard 68 is provided with a stub shaft which extends vertically into a bearing 60, mounted on the carriage. This insures that friction and wear-which normally cause diilicult lubrication problems when a thread engages a pillow block or the like-will be largely overcome, since roller 61 rotates.with the lead screw, and also turns in accordance with the pitch of the thread.

The reversible drive between drive gear 24 and spur gear 66, keyed to the lead screw, includes, as in Fig. 3, a bevel pinion 6|, which effects rotation of the lead screw in one direction, and a bevel pinion 62 which eflects rotation of the lead screw in the opposite direction. Bevel pinions 6| and 62 are rotated' by a double-headed jaw clutch 63 splined on a vertical shaft to which drive gear 24 is keyed and are loosely mounted on this shaft, which rotates in bearings 64. Bevel pinions 6| and 62 alternatively drive a bevel ring gear 66 keyed to a shaft which is mounted in bearing standards 66 and to which is keyed a spur pinion 61. Pinion 61, in turn, meshes with spur gear 66 whichiis keyed to the shaft of lead screw S.

For reversing the direction of rotation of the lead screw, preferably in accordance with the position of the carriage C, a reciprocable rod 68, as in Figs. 4 and 6, is mounted in bearings 69 attached to the platform. An arm 10 is attached to one of beams 45 of the carriage framework, so as to engage a collar or stop H on rod 68 as one end of its travel is reached, and to engage a collar or stop 12 as the end of its travel is reached in the opposite direction. Stops II and 12 are attached to rod 68 in a suitable manner, as by set screws. With the carriage traveling in the direction of the arrow in Fig. 4, and in the position of Fig. 6, arm ID has just engaged collar ll to push rod 68 to the right, which will also push to the right a, lever 13, pivoted at its lower end on a pin 14 attached to the platform and to the center of which rod 68 is pivotally attached. As lever 13 is pushed to the right, from the full to the dotted position of Fig. 6, an arm 15 attached centrally thereto and extending perpendicularly therefrom, swings with the lever so that one of two actuating pins 16 will strike a lever 11 attached to the outboard end of a clutch operating rod 18. This movement shifts the clutch operating rod 18 so that a fork I9 moves jaw clutch 63 upwardly so that the lower jaw of the clutch will disengage bevel pinion 6|, and the upper jaw of the clutch will engage bevel pinion 62, as will be evident from Fig. 3.

To maintain the clutch in the position to which it is [shifted until the rod is again actuated by movement of the carriage to the opposite end of its traverse, and to assist in shifting the clutch, the upper end of lever 13, as in Fig. 6, is provided with a cage 80 in which a weight 8| will roll from left to right, as from the full to the dotted position of Fig. 6, when the lever is moved from left to right so that the slope of the cage is in the opposite direction. Thus, as lever 13 passes across its center line, the weight will roll from left to right, or vice versa, thereby pulling rod 68 along with it and providing a quick-acting clutch reversal movement. Weight 8| also tends to maintain lever 13 in its new position until the lever is shifted past its center-line by movement of the carriage in the opposite direction. Also, disengagement of the clutch from one gear, which does not require as much force as engagement with the other gear, is accomplished while lever 13 is being pushed up to its center-line, and is resisted by weight 8|, which tends to stop the carriage as soon as the clutch is disengaged. Thus, the strain on the lead screw is reduced in reversing the direction of movement of the carriage.

In addition to the parts above described, suitable electrical controls may be provided, such as the usual switches and relays for controlling motors l5 and 3|. Also, a limit switch may be provided for stopping the feed when coke and limestone reach a predetermined level in the kiln. Such a limit switch may be mounted on the platform P and may be actuated by a rod attached to the feed spout and extending downwardly therefrom. Also, suitable limit switches may be installed on the platform actuated by stops on the carriage, so that motor 3| will operate only if the platform is revolving and the carriage is thereby being reciprocated. A further limit switch may be provided in the bin B, so that the motors l5 and 3| will be started only if there is a supply of coke and limestone in the bin. Platform P may be provided with a kiln access door 83, as in Fig. 4.

With the apparatus operating in the fo' egoing manner, to carry out the method of this invention, the coke and limestone are charged uniformly into the kiln by feed spout 8, and are preheated in the top portion of the kiln. As burned lime is removed from the bottom of the kiln through suitable discharge bars or the like, the mass within the kiln settles down relatively uniformly, and more coke and limestone are fed in at the top. As the mixture of coke and limestone passes downwardly through the kiln, it enters the fire zone where the combustion of the coke and the chemical transformation of the limestone, CaCOa, to burned lime, CaO, takes place. The 00;) produced passes upwardly to preheat the mass of coke and limestone above and is discharged from the kiln through outlets 9, as in Fig. 3. These outlets may be connected by suitable piping with the reaction tanks or other equipment in which the CO2 is utilized.

From the foregoing, it will be apparent that the method and apparatus of this invention insure that coke and limestone will be fed uniformly to the kiln in layers having a depth which is uniform across the kiln. It will also be apparent that the method and apparatus of this invention may be utilized in the charging of other materials to kilns, or other divided materials or mixtures thereof to different types of equipment, such as blast furnaces.

It will additionally be understood that changes and variations in addition to those enumerated may be made, and that other embodiments of the invention may exist, all without departing from the spirit and scope of this invention.

What is claimed is:

1. Apparatus for charging a kiln or the like with divided material, comprising a rotating platform; a carriage mounted for radial movement on said platform and carrying a feed spout; and a screw having a varying pitch for reciprocating said carriage at a variable rate on said platform.

2-. Apparatus for charging a kiln or the like with divided material, comprising a rotating platform; a reciprocating carriage mounted for radial movement on said platform; a feed spout carried by said carriage; a, conveyor mounted on said carriage and connecting with said feed spout; means for reciprocating said carriage at a progressively varying rate which is greater adjacent the center of said kiln than adjacent the periphery thereof and stationary means for supplying such material to said conveyor.

3. Apparatus for charging a kiln or the like with divided material, as defined in claim 2, including means for regulating and maintaining uniform the amount of material carried by said conveyor to said feed spout.

4. Apparatus for charging a kiln or the like with divided material, comprising a rotating platform; a reciprocating carriage mounted for radial movement on said platform; a feed spout carried by said carriage and extending through said platform into said kiln; a conveyor on said carriage for supplying substantially equal increments of material to said feed spout; means for reciproeating said carriage to move said carriage at a greater rate when said feed spout is disposed near the center of said kiln than when said feed spout is disposed near the periphery of said kiln; and a stationary bin for supplying such material to said conveyor, such bin having an outlet disposed centrally with respect to said rotating platform.

5. Apparatus for charging a vertical, circular kiln or the like with a mixture of divided material having components tending to segregate in said kiln, comprising a platform mounted atop said kiln, and rotatable with respect thereto; a bin containing the mixture of divided material and having an outlet above the center of rotation of said platform; a carriage reciprocable across said platform and moving under said bin outlet; a belt conveyor mounted on said carriage and moving beneath said bin outlet; a feed spout depending from said carriage, said platform having an aperture therein through which said feed spout extends and adapted to permit movement of saidfeed spout from a point near the center of rotation of said platform to a point adjacent the periphery of said kiln; a gas-sealing device including a housing disposed on said carriage between the discharge end of said belt and said feed spout, and a shaft having a plurality of radially extending paddles disposed within said housing, said paddles being spaced equally about the periphery of said shaft; means mounted on said platform for rotating said platform; means mounted on said carriage for moving said belt and rotating said sealing device shaft; and means for reciprocating said carriage on said platform, including a variable pitch screw for moving said feed spout at a relatively slow rate across said platform when said spout is adjacent the perimeter of said kiln and for moving said spout at a relatively fast rate when said spout is adjacent the center of said kiln.

6. Apparatus for charging a vertical circular kiln or the like as defined in claim 5, wherein said platform is provided with a liquid storage well defined by an upwardly extending flange surrounding said aperture, and said carriage is provided with a cover having a downwardly extending flange around its edges and adapted to seal off said aperture; said cover extending longitudinally of said carriage for a sufficiently greater d stance than the length of said aperture to permit reciprocation of said carriage without uncovering said aperture; in which the drive for said platform comprises a ring gear mounted adjacent the top of said kiln and a pinion depending from said platform and engaging said ring gear; and in which the drive for said carriage includes a pinion depending from said'platform and engagingsaid ring gear, and a reversing .10 clutch arrangement actuated in accordance with the position of saidcarriage on said platform.

'7. In the art of charging kilns or the like, in which a divided material is fed into the kiln from a location near the top thereof,- the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a given cycle of operation, and causing said feed to discharge into the kiln along a progressive spiral course extending from a point adjacent the periphery of the kiln to a point adjacent the center thereof in an action in which the radial component of said discharge movement increases progressively from the periphery to the center, while the circumferential component of said movement is substantially constant.

8. In the art of charging kilns or the like, in which a divided material is fed into the kiln from a location near the top thereof, the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a given cycle of operation, and causing said feed to discharge into the kiln along a progressive spiral course extending from a, point adjacent the periphery'of the kiln to a point adjacent the center thereof in an action in which the radial component of said discharge movement changes progressively from the periphery to the center,

while the circumferential component of said movement is substantially constant, the rate of said change in radial movement being lesser near the periphery and greater near the center.

9. In the art of charging kilns or the like, in which a divided material is fed into the kiln from a location near-the top thereof, the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a given cycle of operation, and causing said feed to discharge into the kiln along a progressive spiral course extending froma point adjacent the center of said kiln to a point adjacent the periphery thereof in an action in which the radial component of said discharge movement decreases progressively from the center to the periphery, while the circumferential component of said movement is substantially constant.

10. In the art of charging kilns or the like, in which a divided material is fed into the kiln from a location near the top thereof, the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a cycle of operation, said cycle including the deposit of the feed material along successive spiral courses with one said course extending from a point near the periphery of the kiln to a point near its center, and the other extending from a point near the center of the kiln to a point near its periphery, and varying the radial component of said depositing movement in each convolution of the spiral course while maintaining the circumferential component substantially constant to cause a deposit of said feed material over equal areas in each revolution of said cycle.

11. In the art of charging kilns or the like, in which a divided material is fed into the kiln from a location near the top thereof, the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a cycle of operation, said cycle including the deposit of t e feed material along successive spiral courses with one said course extending from a Dointnear the periphery of the kiln to a point near its center, and the other extending from a point near the center of the kiln to a point near its periphery, varying the length of the circumferential component of said depositing movement in each convolution along the spiral course while maintaining the rate of circumferential movement substantiallyficcnstant, and varying the radial component said depositing movement in each convolution of the spiral course to cause a deposit of said feed material over equal areas in each revolution of said cycle.

12. In the artof charging kilns or the like, in which a divided material is fed into the kiln from a location near the top thereof, the improvement which comprises feeding the divided material in substantially uniform quantity and at a substantially uniform rate throughout a cycle of operation, said cycle including the deposit of the feed material along successive spiral courses with one said course extending from a point near the periphery of the kiln to a point near its center, and the other extending from a. point near the center of the kiln to a point near its periphery, and maintaining the rate of circumferential component of the depositing movement substantially uniform while the radial component is varied.

13. Apparatus for charging a kiln or the like with divided material, comprising a feed spout mounted for two-dimensional movement adja-' cent the top of such a kiln with its discharge outlet extending into said kiln, rotary means at the top of the kiln for moving said spout circumferentially of the kiln at a uniform rate, means associated with said rotary means for moving the feed spout radially at a variable rate during said circumferential movement, such radial movement being greater when said feed spout is adjacent the center of said kiln. than when said feed spout is adjacent the periphery of said kiln, and means constructed and arranged to deliver feed material into said spout in a substantially uniform quantity throughout said movements.

14. The method of charging divided material into a vertical kiln or the like, which comprises ing such material into the kiln along a spiral course ranging between a point near the periphery and a point near the central axis of said kiln, and controlling said distributing movement so as to maintain the circumferential rate of movement substantially constant while the radial rate is varied.

15. The-- method of into a vertical kiln or the like, which comprises discharging such material into the kiln alon a spiral course ranging between a point near the periphery and a point near the central axis of said kiln, and controlling said distributing moveadapted to be mounted for two-dimensional movement adjacent the top of such a kiln with its discharge outlet extending into said kiln, driving means arranged to rotate said spout circumferentially of the kiln at a uniform rate, and

means associated with said driving means .for moving said spout radially at a variable rate during said circumferential movement.

17. Apparatus for charging a kiln or the like with divided materials,- comprising a feed spout adapted to be mounted for tw -dimensional movement adjacent the top of such a kiln with its discharge outlet extending into said kiln, driving means arranged to rotate said spout circumferentially of the kiln at a uniform rate, and means associated with said driving means for moving said spout radially at a variable rate dur ing said circumferential movement, the rate of said radial "movement being proportioned inversely to the circumferential area of its movement.

AVERY A. CLARK.

REFERENCES CITED The following references. are of record in the file of this patent:

UNITED STATES PATENTS charging amass material 

